The usual agricultural or garden machine, especially in the relatively low horsepower range of say, six to eight H.P. is economically designed and simplified to the extent that costly "frills" are eliminated and the power axle is simply of the straight through type; i.e., it has no differential. Consequently, although straight-ahead operation is fairly easy, problems occur when the machine is user-guided around corners, since the machine is relatively heavy (200-450 lbs) and is equipped with aggressive tires and the drive tends to keep the machine straight .ahead and it must be manhandled on turns, often a difficult task in tough solids, for example.
Machines of higher horsepower and more expensive construction are equipped with internal steering clutches, usually in combination with differentially connected right and left axles. See, for example, U.S. Pat. No. 3,016,957 to Olson. Thus the steering problems encountered in the use of small, less expensive machines are not encountered.
According to the present invention, the improved system of steering by clutching and braking can be provided either as an after-market expedient or as a factory-installed option, in either case significantly improving the operation of the machine. Also in either case, the design is relatively simple and low-cost. In the after-market version, the units are simple, reliable and can be added to an existing machine with a minimum of alterations in the machine. For controls, operation of the clutches and brakes is via the usual handlebars, in one version effected by swinging the handlebars about the typical pivot provided on the machines for adjusting the lateral position of the handlebars. In other instances, the controls may be of the so-called bicycle type comprising levers arranged conveniently to the user.
The clutch-brake units are symmetrically arranged at opposite sides of the basic transmission casing. The relation between each clutch and brake is that each clutch is normally biased to engagement but is released by retarding the proximate or associated brake.
The system provided by the present invention is aimed primarily at improvements in machines of the six to eight horsepower range manufactured by The Garden Way Mfg. Co. of Troy, N.Y.; although, the system can be easily applied to machines of other manufacture and other types as to nature of work performed; e.g., mowing, plowing, snow plowing, etc.
Features and advantages of the invention will become apparent as a preferred embodiment is disclosed in the ensuing description and accompanying sheets of drawings.